Clothes dryer with pilot flame



Jan. 13,1970 v RLAELMQI 3,489,399.

v CLOTHES DRYER WITH PILOT FLAME Fild May 31, 1968 I v z sheets-$2198; 1

WITNESSES I INVENTOR flwmw Rlchord A. Elmy Mew Jan. 13, 1970 R. A. ELMY 3,489,399

CLOTHES DRYER WITH PILOT FLAME Filed May 31, 1968 2 Sheets-Sheet 2 YFIG.3

United States Patent O US. Cl. 263 8 Claims ABSTRACT OF THE DISCLOSURE A gas burner and standing pilot for a clothes dryer or the like wherein the pilot construction and location are such that the pilot flame is not affected by air flow restrictions and such that parts failure and fuel costs are minimized. To this end the pilot is remotely mounted relative to the main gas stream emanating from the burner and an ignition tube disposed therebetween extending, on its end, into a windshield, and, on its other other end into the inner zone of the mantle type flame established at the outlet of the burner.

BACKGROUND OF THE INVENTION This invention relates, in general, to clothes drying apparatus and, more particularly, to drying apparatus employing gas for heating the circulated air.

Basically there are three types of gas burners for apparatus of the type herein disclosed. Such burners are distinguished, in one manner, by the means utilized for igniting the main gas stream, i.e., standing pilots, glow coils and are igniters. The present invention deals with the standing pilot means for ignition, which as is well known comprises a continuous flow of a relatively small quantity of gas which continuously feeds the pilot flame.

The pilot flame is typically disposed adjacent one end of the burner assembly for ignition of the main gas stream directly, consequently, when the main burned flame changes it characteristics, due to a decrease in air flow, the pilot flame also changes its characteristics. This change produces what is commonly referred to as a soft flame (i.e. improper mixture of gas and air), resulting in a reduction in temperature on the pilot flame sensing mechanism which effects cutoff of the pilot gas supply. Such an occurernce necessitates relighting of the pilot which usually requires a service call by the manufacturers service department. The nuisance of such a situation and the desirability of obviating the problem is quite apparent, both from the standpoint of the consumer and the manufacturer.

In addition to the nuisance caused by an arrangement as discussed above, the heat that is constantly being transferred from the pilot to the main burner and the valves associated therewith due to the impinging of the pilot flame on the burner, shortens the life of these parts. Also, when the dryer is not operating there is a significant rise in the temperature of the dryer components which is undesirable. These problems result from the relatively high energy output of the pilot which is on the order of 750- 1000 B.t.u./hr., such a rating being required when lighting the main ags stream, directly, from the pilot.

Conventional standing pilot type constructions are inconvenient to light since the pilot is located beneath the burner and the burner is mounted in a combustion chamber near the bottom of the dryer cabinet. One solution to this problem has been to provide a mirror so positioned relative to the pilot as to permit viewing of the pilot.

Accordingly, it is the general object of this invention to provide a new and improved gas clothes dryer.

It is a more particular object of this invention to provide in a gas clothes dryer, a standing pilot which is not affected by changes in air flow.

Another object of this invention is to provide, in a gas clothes dryer, a gas burner and standing pilot therefor, which pilot has a sufliciently low energy capacity rating and is so located relative to the burner as to minimize parts failure and fuel costs.

SUMMARY OF THE INVENTION The present invention accomplishes the above-cited objects through the provision of a standing pilot which is remotely supported relative to its associated burner. The pilot is encompassed by a windshield in the form of a perforated box. A substantially tubular ignition tube having one end disposed slightly within the confines of the shield has its other end disposed in the path of the gas emanating from the burner. The last-mentioned end is so disposed as to be in contact with the inner zone of the mantle type flame developed at the burner. It is well known that with this type of flame, the inner zone represents an area where there is a mixture of raw gas and air which remains substantially constant, notwithstanding changes in the outer and center zone due to air flow restrictions.

The ignition tube is provided with a plurality of slots on the front side thereof or in other words, on the downstream side of the gas and air mixture. This enables the mixture to flow into and across the tube and then into the windshield where it is ignited by the pilot. The burning gas then travels from slot to slot back to the main stream for ignition thereof. It is this method of indirect ignition o fthe main gas stream which permits reduction of the pilot rating from aproximately 1000 B.t.u./hr. to B.t.u/hr.

Further objects and advantages of the present invention will become more apparent in view of the following detailed description and drawings forming a part hereof.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of a gas clothes dryer representing the invention;

FIG. 2 is a top plan view of a burner control assembly incorporated in the dryer shown in FIG. 1;

FIG. 3 is a side elevational view of the assembly shown in FIG. 2; and

FIG. 4 is a pictorial representation of a typical mantle flame which is produced by the control assembly shown in FIGS. 2 and 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, especially FIG. 1, reference character 10 designates generally a gas clothes dryer comprising a cabinet structure 11 including a top panel 12 and a back splasher panel 13 housing the controls (not shown) of the dryer. The cabinet structure 11 further comprises an upper front panel 14 having an opening 16 providing access to a basket 17 mounted in a conventional manner for rotation about a horizontal axis. A door structure 15 hingedly secured to the front panel 14 serves to close the opening 16 during operation of the dryer.

A removable service panel 18, only partially shown in FIG. 1, provides access to the interior of the cabinet structure 11, where certain components of the dryer are disposed. For example, a combustion chamber 19', having disposed within the confines thereof a burner control assembly generally indicated by reference character 21, serves as a place for heating of circulated air effected by means of a fan structure 22. The air flows into the cab inet through suitable vents, not shown, into the combustion chamber 19, through a riser duct, not shown, at the rear of the dryer, through a perforated rear wall 23 of the basket 17, through a perforated panel 24 of the door structure 15, through a lint filter 26, front air duct 27, the fan 22 and finally .out of the back of the dryer through an exhaust duct 28 extending from the front to the rear of the cabinet structure 11.

The gas burner assembly 21, as shown in FIGS. 2 and 3, comprises a gas burner 29 having substantially symmetrical half sections 30 and 31, the difference between the half sections being in a substantially bowl-shaped flame spreader portion 32 which is integral with the end of the half section 30. As canbe seen, the intermediate portion of the section 30 is tapered so as-to form a venturi section with the corresponding part of the section 31. The burner 29 further comprises a mixing chamber 33 provided with primary air inlet openings 34 the sizes of which are adapted to be varied by means of an adjustable shutter 36. i

A solenoid valve 37 having electrical terminals 38 adapted to be connected .to conventional control circuitry (not shown) regulates the supply of gas to the burner 29, introduction of gas being to the mixing chamber 33 via a right-angle orifice fitting 39. The main valve 37 is connected to a pilot control valve41 which is, in turn, connected to a pressure regulating valve 42 disposed intermediate the pilot valve 41 and a gas inlet line in the form of a pipe 43.

The pilot control valve 41 compnses, among other things, an inlet 44 and an outlet 46, the latter of which communicates with a standing pilot structure 47 constituting the end 48 of a gas conveying tube 49. Flow of gas to the standing pilot 47 from the valve 41 is controlled by means of a thermocouple 51 which generates a millivoltage output as long as the pilot continues to burn to thereby maintain the valve 41 in an opened condition. Should the pilot flame be extinguished for any reason the absence of heat on theend of a thermocouple 51 effects closure of the valve 41. In accordance with an object of the invention the valve 41 is sized to provide a gas flow rate sufficient to develop an energy output of 150 B.t.u./hr.

The end 48 is disposed in a box-shaped windshield 52 having a plurality of side and bottom walls provided with apertures 53 which allow a predetermined quantity of air flow through the shield. The shield is openedat the top to facilitate lighting of the pilot structure 47. The shield 52 is secured to the burner 29 by means of a bracket 54 and screws 56 and 57.

A gas ignition, tube-like member 58 is secured to an arm 59 of the bracket 54 such that it extends between the shield 52 and the outlet of the venturi section formed by half sections and 31. As shown in FIGS. 2 and 4, the one end of the tube 58 extends into the shield 52 while the opposite end thereof extends into the inner zone 61 of the mantle type flame 62 created at the bowl 32. The outside zone 63 and the center zone 64 represent combustible zones whereas the zone 61 represents purely an area of air and natural gas mixture. The tube 58 is provided with a plurality of slots 66 which carry the flame from the pilot structure 47 to the main gas stream adjacent the flame spreader bowl 32. The end of the tube 58 adjacent the outlet of the venturi section is tapered as indicated at 67 to facilitate flow of gas into the tube 58 and subsequently to the shield 52. The entire assembly 21 is supported in the cabinet structure 11 by means of a bracket mounting structure generally indicated at 68.

Cir

Since numerous changes may be made in the aboveapparatus and different embodiments may be made without departing from the spirit thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Clothes dryer apparatus, comprising:

a combustion chamber, 7

fan and air duct structure communicating with said combustion chamber, said fan elfecting circulation of air therethrough,

a gas burner in said chamber,

valve means for controlling flow of combustible gas to said' burner,

a standing pilot for igniting raw gas and air mixture emanating from said burner, said standing pilot being remote from said burner,

means including temperature responsive means for controlling the flow of gas to said standing pilot,

means providing communication between said standing pilot and said burner for conveying a gas mixture from the latter to the former for ignition of the gas, the flame created by said ignition traveling back to said burner 'via said communicating means to thereby ignite the main stream of gas in the area of said burner.

2. Structure as specified in claim 1 wherein,

said communicating means comprises an apertured tube-like, member.

3. Structure as specified in claim 2 wherein,

said means for controlling gas flow to said standing pilot limits the rate of flow to limit energy output of said standing'pilot ,to B.t.u./hr.

4. Structure as specified in claim 3 including a shield comprising apertured enclosure surrounding said standing pilot.

5. Structure asspecified in claim 2 wherein,

' said apertured tube-like member has a tapered end adjacent said burner and has its opening facing the flow of gas.

6. Structure as specified in claim 5 wherein,

, said tube extends slightly into said shield.

7. Structure as specified in claim 6 wherein,

said shield has an opening in the top thereof of sulficient size to permit lighting of said standing pilot. 8. Structure as specified in claim 1 wherein, said communicating means comprises a tube-like member having one end extending into a zone of the flame established at the burner, which constitutes a raw gas and air mixture whereby fluctuation of air flow does not affect the pilot flame.

References Cited UNITED STATES PATENTS 1,983,863 12/1934 Mantz 431-286 X 2,011,097 8/1935 Wantz 431-286 X 2,498,172 2/ 1950 Mintner et al.

3,139,273 6/ 1964 Pittendreigh.

JOHN T. CAMBY, Primary Examiner US. 01. X.R. 26333; 431286 

